ADAMTS2 (A Disintegrin and Metalloproteinase With Thrombospondin Motifs 2) is recognized as a metalloproteinase that promotes the cleavage of amino propeptides of types I, II, III, and V procollagens. However, the role of ADAMTS2 in the heart has not yet been defined. Herein, we observed the upregulated expression of ADAMTS2 in failing human hearts and hypertrophic murine hearts. Mice lacking ADAMTS2 display exacerbated cardiac hypertrophy on pressure overload–induced hypertrophic response, whereas mice with cardiac-specific overexpression of ADAMTS2 display alleviation of this detrimental phenotype. Consistent with these results, in vitro loss or gain of function experiments in neonatal rat cardiomyocytes confirmed that ADAMTS2 negatively regulates cardiomyocyte hypertrophy in response to Ang II. Mechanistically, blockage of the PI3K (phosphoinositide 3-kinase)/AKT (protein kinase B)–dependent signaling pathway with specific inhibitors both in vivo and in vitro could rescue the aggravated hypertrophic response to the loss of ADAMTS2. Collectively, we propose that ADAMTS2 regulates the hypertrophic response through inhibiting the activation of the PI3K/AKT-dependent signaling pathway. Because ADAMTS2 is an extracellular protein, it could be effectively manipulated using pharmacological means to modulate cardiac hypertrophy.

To examine whether transient over-expression of angiopoietin-1 (Ang-1) increases the potency of hiPSC-CMs for treatment of heart failure. Atrial hiPSC-CMs (hiPSC-aCMs) were differentiated from hiPSCs and purified by lactic acid and were transfected with Ang-1 (Ang-1-hiPSC-aCMs) plasmid using lipoSTEM. Ang-1 gene transfection efficiency was characterized in vitro. Gene transfected CMs (1x10⁶) were seeded into a fibrin/thrombin patch and implanted on the rat infarcted left ventricular anterior wall after myocardial infarction (MI). Echo function was determined at 1- and 6- weeks post-MI. Immunohistochemistry study was performed at week-6 post-MI. Ang-1 (20 and 40 ng/ml) protected hiPSC-aCMs from hypoxia through up-regulating pERK1/2 and inhibiting Bax protein expressions. Ang-1-hiPSC-aCMs transiently secreted Ang-1 protein up to 14 days, with peak level on day-2 post-transfection (24.39±13.02 ng/ml) in vitro. Animal study showed that transplantation of Ang-1-hiPSC-aCM seeded patch more effectively limited rat heart apoptosis at 1-day post-MI as compared with LipoSTEM-Ang-1 or hiPSC-aCMs transplantation. Ang-1-hiPSC-aCMs transplantation induced host (rat) and donor (human) CM mitosis and arteriole formation, improved cell engraftment rate, more effectively limited left ventricle (LV) dilation (EDV=460.7±96.1 μl and ESV=219.8±72.9 μl) and improved LV global pump function (EF = 53.1±9%) as compared with the MI (EDV=570.9±91.8 μl, p = 0.033; ESV=331.6±71.2 μl, p = 0.011; EF = 42.3±4.1%, p = 0.02) or the LipoSTEM-Ang-1 injected (EDV=491.4±100.4 μl, p = 0.854; ESV=280.9±71.5 μl, p = 0.287; EF = 43.2±4.6, p = 0.039) or hiPSC-CM transplanted (EDV=547.9±55.5 μl, p = 0.095; ESV=300.2±88.4 μl, p = 0.075; EF = 46±10.9%, p = 0.166) animal groups at 6 weeks post-MI and treatment. Transient overexpression of Ang-1 enhanced hiPSC-aCM mitosis and engraftment and increased the reparability potency of hiPSC-aCMs for treatment of MI. Cellular cardiomyoplasty using hiPSC-CMs alone may be insufficient to recover the structure and function of infarcted myocardium in which blood vessels and perfusion are damaged. A combinational approach of myogenesis with vasculogenesis to repopulate CMs with functional neovascular network is necessary to recover LV structure and function post-MI. This is the first report showing evidence that transplantation of hiPSC-CM transiently overexpressing Ang-1 had better cell engraftment and improved heart structure and function post-MI. It highlights that transient genetic modification of hiPSC-CMs with Ang-1 using non-viral vectors offers a better CM based angiomyogenesis therapy for treatment of MI.

Background: Acute kidney injury (AKI) is a major complication following cardiac surgery that substantially increases morbidity and mortality. Current diagnostic guidelines based on elevated serum creatinine and/or the presence of oliguria potentially delay its diagnosis. We presented a series of models for predicting AKI after cardiac surgery based on electronic health record data. Methods: We enrolled 1457 adult patients who underwent cardiac surgery at Nanjing First Hospital from January 2017 to June 2019. 193 clinical features, including demographic characteristics, comorbidities and hospital evaluation, laboratory test, medication, and surgical information, were available for each patient. The number of important variables was determined using the sliding windows sequential forward feature selection technique (SWSFS). The following model development methods were introduced: extreme gradient boosting (XGBoost), random forest (RF), deep forest (DF), and logistic regression. Model performance was accessed using the area under the receiver operating characteristic curve (AUROC). We additionally applied SHapley Additive exPlanation (SHAP) values to explain the RF model. AKI was defined according to Kidney Disease Improving Global Outcomes guidelines. Results: In the discovery set, SWSFS identified 16 important variables. The top 5 variables in the RF importance matrix plot were central venous pressure, intraoperative urine output, hemoglobin, serum potassium, and lactic dehydrogenase. In the validation set, the DF model exhibited the highest AUROC (0.881, 95% confidence interval [CI] 0.831–0.930), followed by RF (0.872, 95% CI 0.820–0.923) and XGBoost (0.857, 95% CI 0.802–0.912). A nomogram model was constructed based on intraoperative longitudinal features, achieving an AUROC of 0.824 (95% CI 0.763–0.885) in the validation set. The SHAP values successfully illustrated the positive or negative contribution of the 16 variables attributed to the output of the RF model and the individual variable’s effect on model prediction. Conclusions: Our study identified 16 important predictors and provided a series of prediction models to enhance risk stratification of AKI after cardiac surgery. These novel predictors might aid in choosing proper preventive and therapeutic strategies in the perioperative management of AKI patients.

Non-viral transfection of mammalian cardiomyocytes (CMs) is challenging. The current study aims to characterize and determine the non-viral vector based gene transfection efficiency with human induced pluripotent stem cells (hiPSCs) derived cardiomyocytes (hiPSC-CMs). hiPSC-CMs differentiated from PCBC hiPSCs were used as a cell model to be transfected with plasmids carrying green fluorescence protein (pGFP) using polyethylenimine (PEI), including Transporter 5 Transfection Reagent (TR5) and PEI25, and liposome, including lipofectamine-2000 (Lipo2K), lipofectamine-3000 (Lipo3K), and Lipofectamine STEM (LipoSTEM). The gene transfection efficiency and cell viability were quantified by flow cytometry. We found that the highest gene transfection efficiency in hiPSC-CMs on day 14 of contraction can be achieved by LipoSTEM which was about 32.5 ± 6.7%. However, it also cuased poor cell viability (60.1 ± 4.5%). Furthermore, a prolonged culture of (transfection on day 23 of contraction) hiPSC-CMs not only improved gene transfection (54.5 ± 8.9%), but also enhanced cell viability (74 ± 4.9%) by LipoSTEM. Based on this optimized gene transfection condition, the highest gene transfection efficiency was 55.6 ± 7.8% or 34.1 ± 4%, respectively, for P1C1 or DP3 hiPSC line that was derived from healthy donor (P1C1) or patient with diabetes (DP3). The cell viability was 80.8 ± 5.2% or 92.9 ± 2.24%, respectively, for P1C1 or DP3. LipoSTEM is a better non-viral vector for gene transfection of hiPSC-CMs. The highest pGFP gene transfection efficiency can reach >50% for normal hiPSC-CMs or >30% for diabetic hiPSC-CMs.

Caspase recruitment domain 6 (CARD6), a crucial member of the CARD family, was initially shown to be involved in the immune system and oncogenesis. However, the role of CARD6 in chronic pressure overload–induced cardiac hypertrophy remains unexplored. To evaluate the impact of CARD6 on pathological cardiac hypertrophy, cardiac-specific CARD6 knockout mice and transgenic mice with cardiac-specific CARD6 overexpression were generated and subjected to aortic banding for 4 weeks. Our results demonstrated that CARD6-deficient mice aggravated aortic banding–triggered cardiac hypertrophy, ventricular dilation, fibrosis, and dysfunction, as measured by echocardiography, immunostaining, and molecular/biochemical analyses. Conversely, CARD6-overexpressing mice exhibited an attenuated hypertrophic response to chronic pressure overload. Similarly, using cultured neonatal rat cardiomyocytes, we found that adenovirus vector–driven overexpression of CARD6 dramatically limited angiotensin II–induced myocyte hypertrophy, whereas knockdown of CARD6 by AdshCARD6 (adenoviral short hairpin CARD6) exhibited the opposite phenotypes. Furthermore, analysis of the signaling events in vitro and in vivo revealed that CARD6-mediated protection against cardiac hypertrophy was attributed to the interruption of mitogen-activated protein kinase kinase (MEK) kinase-1–dependent MEK-extracellular signal-regulated protein kinase 1/2 (ERK1/2) and c-Jun N-terminal kinase 1/2 (JNK1/2) activation. Altogether, these data indicated that CARD6 serves as a novel cardioprotective factor via negative regulation of MEK kinase-1–dependent MEK-ERK1/2 and JNK1/2 signaling. Thus, our study suggests that CARD6 may be a novel target for the treatment of pathological cardiac hypertrophy and failure.